1. Field of the Invention
The present invention relates to a system and method for driving a thin film transistor liquid crystal display (TFT-LCD), and particularly, to a TFT-LCD driving system and its method for a terminal using the TFT-LCD as its display device.
2. Description of the Prior Art
Recently, a variety of personal portable terminals, such as a mobile phone, a smart phone, a PDA phone providing functions as both the mobile phone and a personal digital assistant (PDA), and the like, have been developed and widely used. The various kinds of terminals have display devices and provide a user with information through the display devices. Recently-developed terminals provide enhanced multimedia functions to thereby reproduce high-resolution moving images. Also, since a terminal provided with a digital camera is coming into wide use, display devices that can offer good image quality are being required.
The terminal commonly uses a thin film transistor liquid crystal display (TFT-LCD) module as a display device, and the TFT-LCD module displays data through its own interface technique with a CPU or a video controller. As for the interface technique of the TFT-LCD module, there are an RGB interface, a data enable interface and the like. In the prior art, an interface between a main CPU or a video controller and the TFT-LCD, a display device, in one terminal is implemented as only one technique.
Hereinafter, an interface between a CPU or a video controller and a TFT-LCD module in a terminal in accordance with the prior art will be described with reference to FIGS. 1 and 2.
FIG. 1 is a block diagram showing a TFT-LCD driving system of an RGB interface technique in accordance with the prior art.
FIG. 2 is a block diagram showing a TFT-LCD driving system of a data enable interface technique in accordance with the prior art.
As shown in FIGS. 1 and 2, the TFT-LCD modules having respectively different interface techniques are not compatible with each other in one TFT-LCD driving system in accordance with the prior art. Therefore, TFT-LCD modules having different interface techniques are driven by different driving systems.
Namely, the TFT-LCD system can use only a TFT-LCD module having the same interface technique as its interface technique. For this reason, when it is intended that TFT-LCD modules having respectively different interface techniques are used in one terminal, different systems should be implemented as shown in FIGS. 1 and 2. Accordingly, there is an increasing need of a circuit structure and an interface method allowing TFT-LCD modules having different interface technologies to be used in one terminal.
A TFT-LCD module of an RGB interface technique requires three signal pins (i.e., a horizontal synchronization pin, a vertical synchronization pin, a data enable pin) in order to synchronize an LCD display screen while the TFT-LCD module of a data enable interface technique requires only one signal pin (i.e., data enable pin) in order to synchronize an LCD display screen. Because the data enable signal inputted to the data enable pin contains information on a horizontal synchronization signal and a vertical synchronization signal, the data enable interface technique desirably requires a small number of control signals compared with the RGB interface technique and can reduce the number of pins from three to one.
However, the TFT-LCD system using only one interface technique has compatibility problems since the system cannot use both TFT-LCD modules having respective different techniques.